Numerical implementation of constitutive integration for rate-independent elastoplasticity

Zeng, Ling Fu; Horrigmoe, Geir; Andersen, R.G.

doi:10.1007/bf00376135

Cited by 12 publications

(1 citation statement)

References 9 publications

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“…For other models, numerical implementation may need to be made for interfacing with finite element software. Such an implementation plays en equally important role as the constitutive models themselves for the accuracy and reliability of the ratcheting simulation [24].…”

Section: Non-linear Finite Element Analysismentioning

confidence: 99%

More on Fatigue Verification of Class 1 Nuclear Power Piping According to ASME BPV Code

Zeng¹,

Jansson²

2014

JEPE

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Fatigue verification of Class 1 nuclear power piping according to ASME Boiler and Pressure Vessel Code, Section III, NB-3600, which is often discussed in connection to power uprate and life-extension of aging reactors in recent years, is dealt with. Key parameters involved in the fatigue verification, e.g., the alternating stress intensity S alt , the penalty factor K e and the cumulative damage factor U, and relevant computational procedures applicable for the assessment of low-cycle fatigue failure using strain-controlled data, are particularly addressed. A so-called simplified elastic-plastic discontinuity analysis for alternative verification when fatigue requirements found unsatisfactory, and the procedures provided in NB-3600 for evaluating the alternating stress intensity S alt, are reviewed in detail. An in-depth discussion is given to alternative procedures suggested earlier by the authors using nonlinear finite element analyses, which uses a nonlinear finite element analysis for directly determining the alternating stress, thus eliminating uncertainties resulted from the use of the penalty factor K e . Using this alternative, unavoidable plastic strains can be correctly taken into account in a computationally affordable way, and the reliability of the verification will not be affected by uncertainties introduced in the simplified elastic-plastic analysis.

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Section: Non-linear Finite Element Analysismentioning

confidence: 99%

More on Fatigue Verification of Class 1 Nuclear Power Piping According to ASME BPV Code

Zeng¹,

Jansson²

2014

JEPE

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Error indicators and mesh refinements for finite-element-computations of elastoplastic deformations

Barthold

Schmidt

Stein

1998

Computational Mechanics

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Many interesting tasks in technology need the solution of complex boundary value problems within the mathematical theory of elastoplasticity. Error controlled adaptive strategies should be used in order to achieve a prescribed accuracy of the computed solutions at minimum cost. Local error indicators in the primal form of the ®nite-element-method for Hencky-and Prandtl±Reuû-plasticity without and with nonlinear hardening are presented, controlling global errors of equilibrium, plastic strain rates, the yield condition and the numerical integration of the¯ow rule. A 2D ®nite element code was extended for the transfer of physical parameters between meshes and for a combined space and time adaptive strategy. All error indicators are tested with the benchmark example of a rectangular plane strain problem with a hole. IntroductionIn the adaptive Finite-Element process, aside from the stepwise optimal choice of the spatial discretization we have to pay attention to the implicit time-dependency of the deformation process.Therefore, special attention has to be devoted to adaptive re®nement and coarsening algorithms for mesh and load-step sizing. The usual decomposition of FEM in space and FDM in time is used which does not permit a rigorous coupled a posteriori error analysis.Thus, an heuristic assumption based on the comparison of Prandtl±Reuû elastoplasticity with Hencky plasticity, i.e. nonlinear elasticity, is used to split the in¯uence of the error of plastic deformation into spatial and time discretization errors [5,7].In this paper three separate local spatial error indicators are derived from global error investigations, namely for equilibrium, plastic strains using the plastic dissipation and the yield condition. Each of them yields a scaled local indicator for mesh re®nement. The error within the integration of the¯ow rule by the backward-Euler scheme is estimated by the maximal change of the normal with respect to the yield surface between two time (load) steps. Additionally, the error by updating and interpolation of the material parameters to an adapted mesh has to be considered, at least by a further iteration step of the weak equilibrium conditions before the next load step.A new technique is given for a staggered combination of adaptivity in space and time and compared with the procedure by Ladeve Áze et al. [10].In the next chapter, the basic equations for elastoplastic deformations with hardening are given pointing out the differences between the Hencky-deformation theory and the Prandtl±Reuû-¯ow-theory. The choice of an adequate ®nite element is treated in section three. The fourth section regards algorithmic questions such as the combination of space and time adaptivity during the computation, the data transfer between different meshes, as mentioned above, and the differences between global and local error estimations. The ®fth section describes the benchmark example used for the numerical tests. Section six presents the different sources of errors in elastoplastic deformations as well as the error es...

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A sequential linear complementarity problem for multisurface plasticity

Zhao

Zhou

et al. 2022

Applied Mathematical Modelling

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Numerical implementation of constitutive integration for rate-independent elastoplasticity

Cited by 12 publications

References 9 publications

More on Fatigue Verification of Class 1 Nuclear Power Piping According to ASME BPV Code

More on Fatigue Verification of Class 1 Nuclear Power Piping According to ASME BPV Code

Error indicators and mesh refinements for finite-element-computations of elastoplastic deformations

A sequential linear complementarity problem for multisurface plasticity

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